1. Field of the Invention
The present invention relates to a method for producing packed tofu (bean curd) which is easily released from the container without leaving a residue in the container.
2. Description of the Related Art
Tofu is roughly divided according to the process of preparation into (1) cut tofu which is obtained by coagulating soybean milk in a mold, cut to size, and kept in water, and (2) packed tofu which is obtained by filling a small container of given size with soybean milk containing a coagulant, sealing the container, and allowing the soybean milk to coagulate in the sealed container. Nowadays packed tofu predominates over cut tofu from the standpoint of shelf life, convenience of distribution, and so forth.
Since packed tofu is made by coagulation of soybean milk as packaged in a container, it has a disadvantage that tofu is in tight contact with the container. Simply turning the container upside down is not able to release tofu from the container in its perfect shape without leaving part of tofu stuck to the container. Various manipulations have been taken to solve this problem. Typical manipulations include using an increased amount of a coagulant, setting the coagulation temperature higher than usual, or heating for a longer time than usual to cause strong coagulation thereby to separate some water content to make a water layer between tofu and the container. Although these methods are successful in facilitating removal of tofu from the container, use of a coagulant more than necessary or the raised coagulation temperature deteriorates the taste or texture of tofu.
There is a method comprising preheating soybean milk before addition of a coagulant at 18 to 30° C. to make water separate on coagulation (Japanese Patent 2936175). However, water separation by this method results from impairment of the water retentive properties inherently possessed by tofu, and the whole tofu structure appears to be loose. Therefore, the texture cannot be necessarily seen as elastic as naturally expected of tofu.